Role of estrogen receptor in endometrial cancer initiation and progression

描述（由申请人提供）： 雌激素受体在子宫内膜癌发生和发展中的作用30年来的流行病学研究表明，非对抗性雌激素激活雌激素受体（ER）信号通路是子宫内膜癌形成的危险因素。尽管如此，关键问题仍然没有答案。(1)为什么只有少数女性，而不是所有的女性，暴露于非对抗性雌激素会发生子宫内膜癌？(2)ER介导的机制是什么，可以导致子宫内膜癌的形成？(3)雌激素效应在子宫内的什么部位介导，子宫内膜上皮和/或间质？研究子宫内膜癌的一个主要限制是缺乏小鼠模型，主要是由于缺乏子宫内膜上皮细胞特异性启动子。最近，我们有一个突破，在我的实验室建立了一个在体内子宫内膜再生模型，从子宫内膜上皮细胞和基质的分离群体。该系统可用于测定两个重要的生物学参数在孤立的子宫内膜细胞亚群：细胞自主和旁分泌致癌刺激的反应。通过生长因子缺失PTEN或旁分泌信号传导的PI3激酶轴的细胞自主激活是涉及子宫内膜癌的起始和进展的两种途径，但这些途径中的每一种与雌激素受体信号传导相互作用的机制尚未确定。虽然ER 1和ER 2都在子宫内膜中表达，但基于功能研究，ER 1-本研究中概述的研究的主要焦点-被认为是该组织中ER的主要形式。在这个建议中，我们计划描绘上皮特异性作用的ER 1在合作与细胞自主和旁分泌致癌信号在子宫内膜癌。我们推测上皮ER 1的激活可能与细胞自主信号如PI3激酶通路的激活协同作用。通过ER 1的信号传导可能是由细胞自主或旁分泌致癌信号介导的子宫内膜增生和癌症的启动所必需的。癌源性旁分泌生长因子信号可能导致ER 1的配体非依赖性激活，这可能是子宫内膜癌进展到激素难治性状态的关键途径。我们的具体目标是（1）检测子宫内膜中PI3激酶和ER 1信号传导轴的激活之间的潜在协同作用。将从PTENloxP/loxP小鼠收获的子宫内膜上皮细胞用ER 1和Cre重组酶慢病毒感染，导致PTEN缺失和ER 1过表达。将这些细胞置于体内子宫内膜再生模型中，并将其肿瘤形成能力与对照进行比较。(2)评估上皮ER 1是否在子宫内膜增生或癌的形成中必不可少。使用Cre-loxP重组系统，将从floxed ER 1小鼠收获的子宫内膜上皮中缺失ER 1，并评估其对旁分泌或细胞自主致癌信号的反应。(3)确定旁分泌生长因子信号传导在ER 1的配体依赖性和非依赖性激活中的作用。逆转录病毒递送载体将用于在子宫内膜基质细胞中表达候选生长因子。将表达生长因子的基质细胞与成人分离的子宫内膜上皮细胞重组，并置于体内子宫内膜再生模型中。Western印迹和免疫组织化学将用于评估对照和生长因子过表达再生移植物中ER 1信号传导的活化。本研究的发现可以明确ER 1信号在子宫内膜癌的发生和发展中的上皮特异性作用，以及细胞自主和旁分泌致癌信号。我们的研究结果可能对ER 1信号驱动的子宫内膜肿瘤患者亚群具有重要意义，ER 1可能是有效的治疗靶点。这项建议的结果可能是一个步骤，对这种常见的妇科恶性肿瘤的个性化治疗，在不断增长的女性退伍军人的人口。 公共卫生相关性： 子宫内膜癌占美国女性生殖器癌症的50%（1）。子宫内膜癌的发病率随着年龄的增长而上升，80%的患者在绝经后被诊断出来。通过激素替代疗法或无排卵月经长期暴露于高水平的雌激素是子宫内膜癌的主要危险因素。据记载，战争和战斗引起的压力导致月经异常的发生率在暴露于战场的女性中高达35%（2）。因此，在未来几年内，子宫内膜癌的发病率可能会上升的老年女性退伍军人受到压力，因此月经不规律。虽然子宫内膜癌的预后在疾病的早期阶段是有利的，但晚期或复发性疾病的患者预后较差。对于晚期疾病，化疗和/或放疗的反应率低于50%（3）。有针对性的治疗可以为诊断患有这种疾病的女性退伍军人提供显着的改善。1. a. Jemal等人，CA Cancer J Clin 59，225（2009年7月-8月）。2. a. B。Hannoun，A. H.纳萨尔岛M. Usta，T. G. Zreik，A. a. Abu Musa，Obstet Gynecol 109，929（2007年4月）。3. D. Pectasides、E. Pectasides，T. Economopoulos，Cancer Treat Rev 33，177（Apr，2007）.

DESCRIPTION (provided by applicant): Role of Estrogen Receptor in Endometrial Cancer Initiation and Progression Epidemiologic studies dating back thirty years demonstrated that activation of the estrogen receptor (ER) signaling pathway by unopposed estrogen is a risk factor for the formation of endometrial carcinoma. Despite this observation, critical questions remain unanswered. (1) Why do only subsets, and not all women, exposed to unopposed estrogen develop endometrial cancer? (2) What are the ER mediated mechanisms that can lead to the formation of endometrial cancer? (3) Where in the uterus are estrogenic effects mediated, endometrial epithelium and/or stroma? A major limitation in studying endometrial cancer has been a paucity of mouse models, predominantly due to a lack of endometrial epithelial cell-specific promoters. Recently we have had a breakthrough in my laboratory with the establishment of an in vivo endometrial regeneration model from dissociated populations of endometrial epithelium and stroma. This system can be used to assay two important biological parameters in isolated subpopulations of endometrial cells: response to cell autonomous and paracrine oncogenic stimuli. Cell autonomous activation of the PI3Kinase axis via deletion of PTEN or paracrine signaling by growth factors are two pathways implicated in the initiation and progression of endometrial cancer, but mechanisms through which each of these pathways can interact with estrogen receptor signaling has not been determined. While ER 1 and ER 2 are both expressed in the endometrium, based on functional studies ER 1 - the main focus of the outlined studies in this grant - is thought to be the predominant form of ER in this tissue. In this proposal, we plan to delineate the epithelial specific role of ER 1 in cooperation with cell autonomous and paracrine oncogenic signals in endometrial cancer. We hypothesize that activation of epithelial ER 1 can cooperate with cell autonomous signals such as PI3Kinase pathway activation. Signaling through ER 1 may be essential for the initiation of endometrial hyperplasia and cancer mediated by cell autonomous or paracrine oncogenic signals. Oncogenic paracrine growth factor signals may lead to ligand independent activation of ER 1, which may be a critical pathway for the progression of endometrial cancer to a hormone refractory state. Our specific aims are (1) Examine potential synergy between the activation of the PI3Kinase and the ER 1 signaling axes in the endometrium. Endometrial epithelial cells harvested from PTENloxP/loxP mice will be lentivirally infected with ER 1 and Cre- recombinase resulting in deletion of PTEN and over expression of ER 1. These cells will be placed in the in vivo endometrial regeneration model and their tumor forming capacity will be compared to controls. (2) Assess whether epithelial ER 1 is essential for the formation of endometrial hyperplasia or cancer. Using a Cre-loxP recombination system, ER 1 will be deleted in endometrial epithelia harvested from floxed ER 1 mice and their response to paracrine or cell autonomous oncogenic signals will be assessed. (3) Determine the role of paracrine growth factor signaling in the ligand dependent and independent activation of ER 1. Retroviral delivery vectors will be used for the expression of candidate growth factors in endometrial stromal cells. Growth factor expressing stromal cells will be recombined with adult dissociated endometrial epithelia and placed in the in vivo endometrial regeneration model. Western blot and immunohistochemistry will be used to assess activation of ER 1 signaling in control and growth factor over expressing regenerated grafts. Findings in this proposal can define the epithelial specific role of ER 1 signaling in the initiation and progression of endometrial cancer in conjunction with cell autonomous and paracrine oncogenic signals. Our findings could have critical implications for the subset of patients with endometrial tumors driven by the ER 1 signaling, in whom ER 1 could be a valid therapeutic target. Results of this proposal could be a step toward individualizing therapy for this common gynecologic malignancy in the growing population of female veterans. PUBLIC HEALTH RELEVANCE: Endometrial cancer accounts for 50% of female genital cancers in the United States (1). The incidence of endometrial cancer rises with age, 80% being diagnosed in postmenopausal patients. Chronic exposure to high levels of estrogen by either hormone replacement therapy or anovulatory menstruation is a major risk factor for endometrial cancer. Incidence of menstrual abnormalities, resulting from stress induced by war and combat, is documented to be as high as 35% in females exposed to the war field (2). Therefore, in the next several years the incidence of endometrial cancer could rise among aging female veterans affected by stress and hence menstrual irregularities. While the prognosis of endometrial cancer is favorable in early stages of disease, patients with advanced stages at presentation or recurrent disease have a poor outcome. With advanced stage disease, response rates to chemotherapy and or radiation is less than 50% (3). Targeted therapy can provide a significant improvement in treating women veterans diagnosed with this disease. 1. A. Jemal et al., CA Cancer J Clin 59, 225 (Jul-Aug, 2009). 2. A. B. Hannoun, A. H. Nassar, I. M. Usta, T. G. Zreik, A. A. Abu Musa, Obstet Gynecol 109, 929 (Apr, 2007). 3. D. Pectasides, E. Pectasides, T. Economopoulos, Cancer Treat Rev 33, 177 (Apr, 2007).